test(vscode): disable application updates and enforce the pinned host version #194

Single local matrix run v-knH1nP for PR #193 downloaded/resolved VS Code 1.134.0, but mysql-extended.json reported 1.135.0 while mysql.json and postgres-extended.json reported 1.134.0. combineHostReports correctly rejected mixed host versions and terminated the run, leaving subsequent hosts unrun. The isolated main.log shows automatic application update checks, downloading, downloaded and ready states. The harness disables extension auto-updates but not application updates.

Set the isolated profile application update policy to none, verify the executable/actual host version for every scenario, and avoid reusing a cache entry whose binary version no longer matches its label. Retain mismatch evidence rather than silently accepting a different version. No retry or fix was performed in this milestone because the user requested exactly one local pass. Related #191 and PR #193. Final compatible matrix snapshot: VS Code 32 passed / 12 failed / 40 not-run; raw MySQL extended results are retained but excluded from aggregation.